Suture welding device

ABSTRACT

Devices for welding suture segments in lieu of tying knots in sutures applied during endoscopic surgery. The devices provide for snaring loose suture ends and drawing the suture ends into a space between heating surfaces, and provide for closing the heating surfaces.

This patent application is a divisional application of application No.09/286,484 filed Apr. 5, 1999, which is U.S. Pat. No. 6,077,277 issuedJun. 20, 2000.

FIELD OF THE INVENTIONS

The devices described below relate to the field of surgical devices andmethods, specifically to the field of endoscopic suturing techniques.

BACKGROUND OF THE INVENTIONS

Sutures and stitching are well known techniques for repairing bodytissue after injury or surgery. Many types of surgery, such as gallbladder removal, hernia repair, and even coronary bypass surgery can nowbe performed through the techniques of endoscopic surgery. Endoscopicsurgery, also referred to as laparoscopic surgery, minimally invasivesurgery, or bloodless surgery, is performed through small incisions inthe body with long slender cutting and grasping devices which can beinserted into the body through the small incisions. The devices havesmall working mechanisms on the distal end (the end of the instrumentthat is inserted into the body) and convenient handles and operatingmechanisms (for controlling the working mechanisms on the proximal end).Surgeons use endoscopic scalpels and scissors for cutting tissue,endoscopic graspers and forceps for grabbing and manipulating tissue,and endoscopic suture needles for stitching tissue. Stitching a surgicalor traumatic wound closed within an endoscopic work space requires quitea bit of manual dexterity and experience, and the final process of tyinga knot in the stitching is very difficult.

Several devices have been suggested for assisting surgeons in securingthe loose ends of a suture during open surgery. Rather than assistingthe surgeon to tie a knot, the devices allow the surgeon to melt the twoloose ends of the suture together or to create a melted mass on a singleloose suture tip which prevents it from being withdrawn into the suturepathway. Zinnbauer, et al, Suture Cutting and Cauterizing Method UsingRadiant Heat, U.S. Pat. No. 5,565,122 (Oct. 15, 1996), while notintended or adapted for endoscopic use, shows a device with jaws mountedat the distal end of a long neck, and a heating element over the jaws.When the jaws are laid against the skin, and the suture is place betweenthe jaws, the heating element is heated to melt the suture and leave amelted mass of suture material on the suture. The melted mass preventsthe suture from being pulled into and through the suture line. Polonsky,Suture Fusing and Cutting Apparatus, U.S. Pat. No. 4,662,068 (May 5,1987) shows a pair of forceps with heat fusing surfaces on the graspingsurfaces of the jaws. The forceps are used to grab and twist two loosesuture ends and melt them together to secure the stitching.

SUMMARY

The devices and methods described below permit the closure of stitchesduring endoscopic surgery. The devices are endoscopic tools capable ofinsertion into an endoscopic access port, such as a cannula, and includea long slender insertion rod with a handle and operating mechanism onthe proximal end and a pair of grasping jaws on the distal end of therod. The grasping jaws are fitted with heating surfaces which can beheated to temperatures sufficient to melt suture. A snare comprised of asnare portion and a rod is housed within the insertion rod. The snareportion can be pushed out the distal end of the insertion rod andmanipulated to snare a length of suture and then pulled proximally intothe insertion rod. The snare may be twisted to create a length oftwisted-together suture. Because the snare is drawn into the insertionrod, the entrapped suture is pulled into the space between the jawswhere it can be grasped and melted by the jaws. This provides an easyway to get the suture between the jaws with limited movement of theinsertion rod within the body and the endoscopic access port. The suturemay be tensioned as desired by the surgeon prior to melting by closingthe jaws firmly on the suture while drawing the snare proximally, thenclosely the jaws tightly so that the suture is held in properlytensioned position while the weld is accomplished.

In one embodiment, the jaws can be scissor-like, having opposinggrasping faces which meet to clamp the suture between the graspingfaces. In another embodiment, the grasping faces are mounted onco-axially disposed tubes, where the tubes rotate relative to the eachother to bring the grasping faces together and close upon the suture.

A composite weldable suture is described below which is particularlyuseful in the creating of melted knots. The suture t comprises a core,which melts at moderately high temperatures compared to a porous fibercover, which melts at a high temperature. When two strands of suture arepressed together and exposed to heat, as in the operation of the suturewelding devices, the cores melt and seep through the fiber cover andfuse together. The presence of the fiber provides structural integrityto the suture which ensures that the melted knot does not separate fromthe standing part of the suture.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a suture welding device for grabbing sutures withinand endoscopic work space and fusing a knot in the suture.

FIG. 2 illustrates a proximal handle design which permits one handedoperation of the suture welding device.

FIG. 3 illustrates a step in the operation of the suture welding deviceof FIG. 1.

FIG. 4 illustrates a step in the operation of the suture welding deviceof FIG. 1.

FIG. 5 illustrates a step in the operation of the suture welding deviceof FIG. 1.

FIGS. 6 and 7 illustrate variations on the snare used with the suturewelding device.

FIG. 8 illustrates a rotary embodiment of the suture welding device.

FIG. 9 illustrates a step in the operation of the suture welding deviceof FIG. 8.

FIG. 10 is an illustration of the suture with a meltable component thatmay be used with the suture welding devices.

DETAILED DESCRIPTION OF THE INVENTIONS

FIG. 1 illustrates a suture welding device 1. The welding device iscomprised of a long insertion rod 2, with a distal end 3 and a proximalend 4. The distal end carries a pair of grasping jaws 5 and 6 mountedpivotably within the distal end and protruding from the distal end ofthe insertion rod. The proximal end is fitted with a handle assembly 7.A snare 8 including a snaring portion 9 mounted on the distal end of asnare rod 10 is slidably and rotatably disposed within the lumen 11 inthe d insertion rod 2. The snare also includes the handle 12 mounted onits proximal end. The snare exits out the distal end of the insertionrod, and as illustrated exits through a port in the distal face 13 ofthe insertion rod. The snare provides a means for initially graspingloose suture ends and drawing the suture ends into close proximity tothe jaws. The jaws provide a second means for grasping the suture endsafter they have been picked up by the snare.

The insertion rod may be any convenient length, typically 30 to 100centimeters, and is preferably of small diameter about 2 mm to 2 cm tofit in standard endoscopic access cannulas. The lumen of the insertionrod may also be configured to exit out the side-wall of the insertionrod, thereby directing the snare rod outwardly in a direction which isdivergent from the long axis of the insertion rod. The snare portion 9is comprised of two arcuate branches of resilient metal or plastic, witheach branch extending distally from the snare rod to curve firstoutwardly from the long axis of the snare rod and then inwardly towardthe long axis of the snare rod to join together at their distal tips.The resilient branches may preferentially open upon exit from the lumen,and be compressible into a narrow configuration upon withdrawal into thelumen. The grasping jaws mounted on the distal end of the insertion rodextend distally from the insertion rod. Each jaw 5 and 6 has a graspingface 17 and 18 which opposes the grasping face on the other jaw, and thejaws may be closed to bring the grasping faces into contact or closeproximity. The grasping face of each jaw includes resistive heatingelements 19 and 20 which are connected to an appropriate power supplythrough electrical wires that run through the jaws and the insertion rodto electrical connector 21 in the handle. The lower jaw 6 holds a suturecutting blade 22 aligned with blade channel 23 on the upper jaw 5. Thegrasping faces may have a serrated, knurled or ridged surface to assistin holding the sutures. The handle assembly 7 may include anycomfortable gripping structure such as a pistol grip or scissor handle,a trigger 24 for operating the jaws, and a switch 25 for applyingelectrical power to the heating elements.

FIG. 2 illustrates a proximal handle design which permits one handedoperation of the suture welding device. The insertion rod 2 comprises abarrel which houses the snare 8 and the operating rod 26 for the jaws(which is pulled proximally to close the jaws). The handle assembly 7 ismounted on the proximal end 4 of the insertion rod. The snare is fixedto a screw 27, so that rotation of the screw results in rotation of thesnare. The screw has high pitch threads, and slide yoke 28 engages thethreads so the longitudinal movement of the slide yoke causes rotationof the screw and snare. When the trigger 29 and yoke are pulleddistally, the yoke eventually meets the stop plate 30 mounted on theproximal end of the screw, and further proximal movement of the triggerresults in withdrawal of the snare loop 9 into the insertion rod. Atthis point, the jaws of the device are open, the snare has rotated toform a twist in any suture segments ensnared in the snare loop, and thesnare loop has been pulled into the insertion rod. Further proximaltravel of the trigger and slide yoke will cause the yoke (and the stopplate) to engage the stop plate 31 which is fixed to the jaw operatingrod 26, and force the operating rod proximally, thereby closing thejaws. The slide yoke is fixed to the trigger 24 through a slot in thehandle assembly barrel 32 and the proximal end of the insertion rod. Thetrigger is slidably mounted in the handle assembly, and is biased tomoved distally when not held or squeezed by the surgeon. The bias may beprovided with spring clips or spring loaded slides, or various otherarrangements. When the jaws are closed upon the sutures, the surgeon mayheat the heating elements by operating a push button switch 25. Whilethe device is illustrated with a grasper having two opposing jaws, itmay be constructed with three or more grasping jaws in mutually opposingrelationship. Likewise, although the snare loop is illustrated as atwo-armed snare, the snare may be constructed with three or more armswhich may be used to ensnare loose suture ends. Additionally, while theoperation of the devices is illustrated with a typical suture structurewhich requires joining two standing parts of the suture structure, threeor more standing parts may be joined in the melted “knot” created by thedevice.

FIGS. 3, 4 and 5 illustrate the use of the suture welding device. InFIG. 3 the distal end of the insertion rod is illustrated in proximityto a surgical incision 40 which has been stitched with suture 41. Thesuture 41 may be any fusible suture, including the suture describedbelow in reference to FIG. 10. The suture segments may be referred to asthe stitches 42, the standing parts 43 and 44 (which are the lengths ofsuture remaining after the knot is welded), the welding portions 45 and46 and the ends 47 and 48 (the ends are removed after the knot iswelded). The snare loop 9 has been extended distally from the lumen 11in the insertion rod 2, and has been manipulated by the surgeon to snarethe ends 47 and 48. FIG. 4 illustrates that the snare and snare rod havebeen pulled proximally to draw the suture ends into the lumen 11,drawing the welding portions 45 and 46 into the space between the jaws.The snare rod has been rotated within the lumen to coil the fusingportions of the suture ends into a length of intertwined suturesegments, referred to as the twist 49. In FIG. 5, the surgeon has closedthe jaws upon the twist 49. The surgeon ensures that enough suture hasbeen taken up in the twist so that the sutured incision is properlyclosed, tensioning the suture by a combination of pulling and twistingto draw the suture into the insertion rod. The suture may be tensionedas desired by the surgeon prior to melting by closing the jaws firmly onthe suture while drawing the snare proximally, then closely the jawstightly so that the suture is held in properly tensioned position whilethe weld is accomplished. The surgeon then applies heating power to theheating elements in the jaws by operating the switch 25 in the handle.The heat fuses the weld portions of each suture into mass that firmlyholds the standing parts together, just as would a well tied knot. Theclosure of the jaws also forces the blade through the suture ends to cutaway any excessive length of suture above the weld. (The blade may beomitted where the suture used with the device is easily separable duringwelding, so the formation of the weld also results in separation of thestanding part from the loose ends. A light tension on the loose endsduring welding is sufficient to separate some sutures.) When the jawsare opened, the melted twist is released from the jaws and remains inplace within the body, just as would the knot. The severed suture ends47 and 48 may be withdrawn from the device by pulling the snare rodcompletely out of the proximal end of the suture welding device. Thesutures may be inserted into the snare using other endoscopicinstruments inserted into the endoscopic workspace through other accessports, and the manipulations necessary to grab the suture and weld it atthe proper place may be monitored with endoscopic cameras which arecommonly used to visualized endoscopic procedures.

FIGS. 6 and 7 illustrate variations of the snare that may be used withthe suture welding device. In FIG. 6, the snare is comprised of twodiverging arms 50 extending from the snare rod and forming a Y togetherwith the snare rod. The arms of the grasper may be closed uponwithdrawal into the lumen of the insertion rod. The bosses 51 on theouter surface of each arm help urge the arms closed as they are impingedupon by the walls of the lumen. In FIG. 7, the snare is comprised of anarcuate branch 52 extending distally from the snare rod and a partialarcuate branch 53 extending proximally from the distal end of the firstarcuate branch 52 back toward the snare rod. Many other embodiments ofsnares may be used.

FIG. 8 illustrates a rotary embodiment of the suture welding device. Thedevice comprises an insertion rod 2 with a distal end 3 and a proximalend 4. The outer tube 54 of the insertion rod houses an inner tube 55which is rotatable within the outer tube. On the distal end of the innertubes, heating anvil 56 and grasping surface 57 are formed from aradially extending boss. The inner and outer tubes have a small slot 58which opens on the distal extremity of each tube. The slot defineslongitudinally aligned slot wall 59 (visible in FIG. 8) and an opposingslot wall 60 (visible in FIG. 9) in the outer tube. A small notch 61 islocated in the slot wall 59, opposite to the heating anvil, to receiveand locate the suture in relation to the heating anvil. The heatinganvil is mounting on one edge of the slot of the inner tube, and extendsradially outwardly from the center axis of the tube and into the slot ofthe outer tube. The grasping surface of the outer tube is disposed onthe slot wall of the outer tube slot which opposes the anvil, so thatrotation of the inner tube rotates the anvil into mating relationshipwith the grasping surface of the outer tube. The proximal end of theinsertion rod 2 is fitted with a handle assembly 62 which enablesrotation of the inner tube 55 to bring the grasping boss 56 into contactor close proximity with the matching grasping surface 57 within thelongitudinally aligned slot on the outer tube. A snare 10 is slidablyand rotatably disposed within the insertion rod 2, within a lumen 63 inthe inner tube 55. The snare 8 includes a snare structure 9 mounted onthe distal end of the snare rod 10 and the handle 12 mounted on thedistal end. The snare exits out the distal end At of the insertion rod,and as illustrated exits through the open lumen of the inner tube. Thesnare is illustrated in the position within the inner tube, indicatingthat the surgeon has operated the snare to snare the suture ends,leaving the standing parts 43 and 44 outside the tube, and placing thewelding portions 45 and 46 within the slot between the anvil and thegrasping face. A cutting blade 64 is disposed on the inner edge of theheating anvil, and provides an easily accessible blade for cutting thesuture ends from the weld. The handle assembly 62 includes a pistol gripwith a trigger switch 65 which is operated by the surgeon to applyelectrical energy to the anvil. An aperture 66 through the proximal endof the barrel 2 and handle assembly accommodates a boss 67 whichprotrudes from the inner tube 55. The boss is fixed to the inner tube,so that the surgeon may push the boss downward to rotate the inner tube,and thereby close the grasping boss 56 upon the matching graspingsurface 57 to grasp and melt the suture as described above.

FIG. 9 illustrates a step in the operation of the rotating suturewelding device of FIG. 8. Again, the surgeon has tensioned the suturesas desired by pulling the appropriate amount of suture into theinsertion rod and/or twisting the suture weld portions together.Tensioning can be accomplished by twisting the standing parts of thesuture and/or drawing the suture proximally in to the rod until thedesired degree of tension is obtained. The surgeon has drawn the sutureend into the insertion rod, and has trapped the welding portions of thesuture between the anvil 56 and the grasping surface 57 by rotating theinner tube relative to the outer tube. Closure of the anvil upon thegrasping surface also results in closure of the blade 64 on the suture,severing the suture ends from the weld portions. (Again, the blade maybe omitted where the suture used with the device is easily separableduring welding, so the formation of the weld combined with light tensionon the loose ends of the suture results in separation of the standingpart from the loose ends.) The weld is made such that the standingportion is of appropriate tension. After the weld is complete, thesuture ends may be removed be pulling the snare rod proximally from thedevice.

FIG. 10 illustrates the suture with a meltable component that may beused with the suture welding devices. The suture 74 is comprised of ameltable core 75 covered by a melt-resistant porous sheath 76. Uponapplication of heat sufficient to melt the core, the core material flowsthrough the porous sheath and flows into core material flowing fromadjoining suture segments. The temperature is maintained below themelting point of the sheath material, so that the sheath does not meltand remains in tact so that the suture does not break or separate uponmelting of the core. Preferably, the core melts at temperatures abovebody temperature but below temperatures which would significantly damagesurrounding body tissue, such as the range of 40° C. to 270° C. (thesetemperatures can be achieved briefly in the heating elements withoutcausing harmful heating in the surrounding body tissue). The poroussheath preferably melts at temperatures above the temperature range inwhich the core melts, preferably being melt resistant to temperaturesexceeding the melting temperature of the core material. The core may bemade of the following materials: polyethylene (120° C.), polypropylene,nylon (200° C.), polyethylene terepthalate (255-270° C.), polyester,polytetrafluoroethylene (PTFE) and ePTFE (Teflon®), polyglycolic acid,polyvinylidene, polylecaprone, polydioxanone, polyglectin, polygalactin,polyvinylidene fluoride and many other thermoplastics. The porous sheathmay be made of the materials such as silk, cotton, catgut, stainlesssteel, polyamide, PTFE, fluorinated ethylene propylene (FEP), and anyone of the above-mentioned core materials that melts at a highertemperature than the selected core material. It should be appreciatedthat many combinations of core and porous sheath materials can beachieved.

Thus, while the preferred embodiments of the devices and methods havebeen described in reference to the environment in which they weredeveloped, they are merely illustrative of the principles of theinventions. Other embodiments and configurations may be devised withoutdeparting from the spirit of the inventions and the scope of theappended claims.

We claim:
 1. A device for securing a plurality of segments of suturetogether, said device comprising: an insertion rod having a distal and aproximal end, said distal end adapted to be inserted into an endoscopicwork space; a first means for grasping the suture, said first meansbeing capable of snaring loose suture ends within an endoscopic workspace, said first means for grasping suture being slidably disposedwithin the insertion rod and being operable from the proximal end of theinsertion rod to grasp at least one segment of suture; a second meansfor grasping the suture, said second means being disposed near thedistal end of the insertion rod, said second means comprising means forheating the suture, a rotatable member within the insertion rod, a sloton the distal tip of the insertion rod, a grasping boss protrudingradially from the rotatable member and outwardly into the slot in theinsertion rod, said rotatable member having a distal end and a proximalend, said slot defining a longitudinally aligned slot wall, said bossdefining a grasping surface opposing the longitudinally aligned slotwall, said rotatable member being rotatable from the proximal end of theinsertion rod to bring the grasping surface of the boss into proximitywith the longitudinally aligned slot wall.
 2. A device for securing aplurality of segments of suture together, said device comprising: abarrel having a distal and a proximal end; a first means for graspingthe suture, said first means being capable of snaring loose suture ends,said first means for grasping suture being slidably disposed within thebarrel and being operable from the proximal end of the barrel to graspat least one segment of suture; a second means for grasping the suture,said second means being disposed near the distal end of the barrel, saidsecond means comprising means for heating the suture, a rotatable memberwithin the barrel, a slot on the distal tip of the barrel, a graspingboss protruding radially from the rotatable member and outwardly intothe slot in the insertion rod, said rotatable member having a distal endand a proximal end, said slot defining a longitudinally aligned slotwall, said boss defining a grasping surface opposing the longitudinallyaligned slot wall, said rotatable member being rotatable from theproximal end of the barrel to bring the grasping surface of the bossinto proximity with the longitudinally aligned slot wall.
 3. A devicefor securing a plurality of segments of suture together, said devicecomprising: an insertion rod having a distal and a proximal end, saiddistal end adapted to be inserted into an endoscopic work space; a firstsuture grasper, said first suture grasper being capable of snaring loosesuture ends within an endoscopic work space, said first suture grasperbeing slidably disposed within the insertion rod and being operable fromthe proximal end of the insertion rod to grasp at least one segment ofsuture; a second suture grasper, said second suture grasper beingdisposed near the distal end of the insertion rod, said second suturegrasper comprising a heating element, a rotatable member within theinsertion rod, a slot on the distal tip of the insertion rod, a graspingboss protruding radially from the rotatable member and outwardly intothe slot in the insertion rod, said rotatable member having a distal endand a proximal end, said slot defining a longitudinally aligned slotwall, said boss defining a grasping surface opposing the longitudinallyaligned slot wall, said rotatable member being rotatable from theproximal end of the insertion rod to bring the grasping surface of theboss into proximity with the longitudinally aligned slot wall.
 4. Adevice for securing a plurality of segments of suture together, saiddevice comprising: a barrel having a distal and a proximal end; a firstsuture grasper, said first suture grasper being capable of snaring loosesuture ends, said first suture grasper being slidably disposed withinthe barrel and being operable from the proximal end of the barrel tograsp at least one segment of suture; a second suture grasper, saidsecond suture grasper being disposed near the distal end of the barrel,said second suture grasper comprising a heating element, a rotatablemember within the barrel, a slot on the distal tip of the barrel, agrasping boss protruding radially from the rotatable member andoutwardly into the slot in the insertion rod, said rotatable memberhaving a distal end and a proximal end, said slot defining alongitudinally aligned slot wall, said boss defining a grasping surfaceopposing the longitudinally aligned slot wall, said rotatable memberbeing rotatable from the proximal end of the barrel to bring thegrasping surface of the boss into proximity with the longitudinallyaligned slot wall.